The work was focused on investigating how Fe-doped CeO2 composites affect the physicochemical properties in relation to the NO + CO reaction. The coprecipitation method was adopted to prepare CeO2FeOx mixed oxides. The NO + CO reaction as well as temperature-programmed reduction, N-2 physisorption, oxygen storage capacity, X-ray photoelectron spectroscopy, X-ray diffraction, and in situ Fourier transform infrared spectroscopy were used to characterize the resulting samples. These results implied that the appropriate doping amount of FeOx would cause an obvious change on the CeO2 structure and properties. Also, the catalyst with the ratio of Ce:Fe = 1:0.35 showed the best catalytic properties. In addition, during calcination, adding a few FeOx molecules could benefit the formation of low-valence Fe to a larger extent. This synergetic effect contributed to the formation of a larger number of Fe2+ and oxygen vacancies.